1. Field of the Invention
This invention relates to methods, apparatuses and satellite-based communication systems in which a transmission power level of a device that receives/transmits data is adjusted depending on changing external conditions.
2. Discussion of the Background
Communication networks that transmit data via electromagnetic waves radiated in air or vacuum are constrained in terms of the available power-bandwidth. For example, it is known that a repeater that retransmits the data from a hub to a remote or from a remote to another remote is capable of retransmitting a limited amount of data at a given time. When multiple users use the remotes to exchange data, each user is assigned a given bandwidth that he might use during any time. In order to control the usage of the assigned bandwidth, the user has to control the amount of power used during the transmission of data.
Thus, under normal conditions, the user sets up the maximum amount of power to be used by the transmitter of the remote. By normal conditions it is understood clear sky, i.e., no clouds or other particles between the remote and the repeater or the repeater and the hub. However, the clear sky condition does not last indefinitely, and periodically clouds or rain is present between the repeater and the remote on their direct line of sight.
When these conditions (fade) are occurring, the remote or the hub has to increase the transmission power in order to transmit data in the assigned bandwidth. However, the remote does not know where the fading is occurring, and thus, the remote increases the power indiscriminately. This approach may result in overusing the assigned power-bandwidth, resulting in penalties imposed by the owner of the bandwidth.
One solution is to increase the power at the remote less than necessary for compensating the fading. However, this approach has the disadvantage that less than the assigned power-bandwidth is used, limiting the transmitting capabilities of the user.